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Three Puzzles in Galactic Extra-planar H I

Published online by Cambridge University Press:  17 September 2012

F.J. Lockman
F.J. Lockman*
Affiliation:
NRAO, PO Box 2 Green Bank, WV, USA
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Abstract

Many phenomena first detected in Galactic H i, such as high velocity clouds and gaseous warps, have now been detected and studied in nearby galaxies. Given this valuable perspective I examine three aspects of Galactic extra-planar gas that appear somewhat puzzling from our vantage in the Milky Way disk. I. Spiral galaxies have a rotation curve that decreases with distance above their mid-plane; where is the lagging halo in the Milky Way? II. Other systems show clear evidence for accretion of neutral gas; where is this gas in the Milky Way? III. Warps of the H i layer are common in the outskirts of disk galaxies; are we confident that we’ve correctly parameterized our own warp? The answers appear to be that lagging halo gas could well be present in the Galaxy but would be difficult to detect; that there is now solid evidence for the accretion of high-velocity H i clouds by the disk, though the details are still mysterious, and that the warp continues to baffle us, as it exhibits a puzzling morphology and kinematics.

Type
Research Article
Information
European Astronomical Society Publications Series , Volume 56: The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall? , 2012 , pp. 189 - 196
Copyright
© EAS, EDP Sciences, 2012

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References

Bland-Hawthorn, J., 2009, in The Galaxy Disk in Cosmological Context, ed. J. Anderson, J. Bland-Hawthorn & B. Nordstrom, IAU Symp., 254Google Scholar
Brüns, C., Kerp, J., Kalberla, P.M.W., & Mebold, U., 2000, A&A, 357, 120
Burke, B.F., 1957, AJ, 62, 90CrossRef
Collins, J.A., Benjamin, R.A., & Rand, R.J., 2002, ApJ, 578, 98CrossRef
Dickey, J.D., & Lockman, F.J., 1990, ARA&A, 28, 215CrossRef
Fraternali, F., & Binney, J.J., 2006, MNRAS, 366, 449CrossRef
Hartmann, D., & Burton, W.B., 1997, Atlas of Galactic Neutral Hydrogen (Cambridge: Cambridge Univ. Press)Google Scholar
Heitsch, F., & Putman, M.E., 2009 [arXiv:0904.1995]
Jiang, I.-G., & Binney, J., 1999, MNRAS, 303, L7CrossRef
Kalberla, P.M.W., Dedes, L., Kerp, J., & Haud, U., 2007, A&A, 469, 511
Kerr, F., 1957, AJ, 62, 93CrossRef
Levine, E.S., Blitz, L., & Heiles, C., 2006, ApJ, 643, 881CrossRef
Levine, E.S., Heiles, C., & Blitz, L., 2008, ApJ, 679, 1288
Lockman, F.J., 2002, ApJ, 580, L47CrossRef
Lockman, F.J., 2003, ApJ, 591, L33CrossRef
Lockman, F.J., Benjamin, R.A., Heroux, A.J., & Langston, G.I., 2008, ApJ, 679, L21CrossRef
Peek, J.E.G., Heiles, C., Putman, M.E., & Douglas, K., 2009, ApJ, 692, 827CrossRef
Pidopryhora, Y., Lockman, F.J., & Shields, J.C., 2007, ApJ, 656, 928CrossRef
Putman, M.E., 2006, ApJ, 645, 1164CrossRef
Rand, R.J., 2005, in Extra-Planar Gas, ed. R. Braun, ASP Conf. Ser., 331, 163
Sancisi, R., Fraternali, F., Oosterloo, T., & van der Hulst, T., 2008, A&AR, 15, 189
Smith, G.P., 1963, Bull. Astr. Inst. Netherlands, 17, 203
Voskes, T., & Burton, W.B., 2006 [arXiv:astro-ph/0601653]